Thread: One edge is sharper than the other

On a microtome and a Japanese razor, there is only one edge.

You can argue it theoretically all you want, the fact remains that I have had numerous razors whose edges looked like the picture I put in, and they would shave on one side and not the other, no matter what angle was used.

I will bow to your experience but I had a couple razors where I did this and played with the angle and will shave at a steep angle in one direction and a shallow one in the other.

Right. As there is a pretty specific way in which one tends to use a razor, the debate about angle of attack seems moot. I am pretty sure that if it were worked into just the right corner you could produce a razor that would only shave if you scraped it across your face with the blade at 90 degrees to the skin. I get what you are saying about there being a bevel that inevitability must arise from two surfaces meeting, but that doesn't get the OP's face smooth. "Angle of Attack" just sounds like compensating for a jacked up bevel.

Originally Posted by holli4pirating

On a microtome and a Japanese razor, there is only one edge.

This is impossible. Please draw a bevel with only one edge.

Mathematical stuff:
Even if one side were curved, at the microscopic level it will approximate a straight line. (definition of a derivative) Whenever two lines intersect an angle is formed. Even if two curves intersect, their intersection is still an angle. In a very extreme case, let us assume one line is horizontal and the other is verticle, forming a ninety degree angle. One only has to rotate it 45 deg and you have a (very wide) bevel.

Originally Posted by khaos

This is impossible. Please draw a bevel with only one edge.

Um... maybe I don't know what "edge" means

How many edges do you count here?

Originally Posted by holli4pirating

Um... maybe I don't know what "edge" means

How many edges do you count here?

So how is that different from a bevel form by the intersection of two faces at different slopes? It still forms an edge/point. Just at a different angle...
if it shaves on one side that means there is an intersection of planes sharp enough to shave and I see no reason why it shouldn't shave from the other side *if you changed your angle of attack*.

Look whatever. I will cede on grounds of experience.

My understanding is that a bevel is different from an edge. As I understand it, the bevel is the area on each side of the razor near the edge where the razor touches the hone and you can see hone wear. The edge is the "line" or "curve" (for a smiling blade) where the bevels intersect.

It would be as though I took a shave ready blade and applied a few layers of tape to one side of the spine. Worked the taped side a bit then shaved.

This is what I am getting at with the "angle of attack". On the top you see a single, normal bevel/edge/whatever. Lets say it forms a 150deg angle with your skin (arbitrary, I don't know what angle it is, but for sake of argument).

In the second line one sees that with the weird formation in question, if you tried to shave normally, one way will be fine, while the other will actually yield a crappy angle, say 95deg (once again arbitrary for argument)

In the third line I am showing how if you flattened it out you could restore the 150deg angle.